Illinois Child Support in 2027: What Changes January 1 (and What Doesn't)
Beginning January 1, 2027, Illinois lowers the number of overnights that triggers the shared-parenting child support formula from 146 to 110 a year, with a sliding adjustment between 110 and 145. The new rule matters when support is set or modified under it. It does not change existing orders, and the new law by itself is not a reason to modify one.
Ask for a 2027 support check · Estimate support under the 2027 rule · This applies whether you pay support or receive it.
What changes on January 1, 2027?
- The shared-care threshold drops to 110 overnights. Under the new rule, shared physical care means each parent exercises 110 or more overnights a year (the threshold was 146), or 110 or more overnight equivalents found by a court as a deviation from the guidelines or agreed by the parents (750 ILCS 5/505(a)(3.8)(1)).
- A sliding adjustment covers 110 to 145 overnights. A parent with fewer than 146 overnights has his or her shared-care obligation increased by 2% to 10% (table below). The statute adds that the adjusted obligation "may not be greater than the amount that would have been ordered under the basic support guidelines in any event" (505(a)(3.8)(3)).
- The minimum-order presumption reaches more low-income parents. The rebuttable presumption of a $40-per-child monthly minimum order reaches a parent with actual or imputed gross income at or below 100% of the federal poverty guideline for one person, up from 75% (505(a)(3.3a)).
- Orders must require an annual income exchange. Support orders entered under Section 505 must require both parents to exchange income information every year, in writing, verifying net income (505(h)).
- Incarceration has a new procedure. The Act adds a modification procedure for a parent incarcerated for more than 180 consecutive days (510(a)(3)).
What does not change?
Existing orders. Nothing in the Act recalculates an order already in place. The amended 750 ILCS 5/510(a) says it directly: "The enactment of a subsequent Public Act itself does not constitute a substantial change in circumstances warranting a modification." Keep paying, or receiving, the amount your order sets until a court changes it.
How parenting time is decided. Courts still allocate parenting time according to the child's best interests (750 ILCS 5/602.7(a)). The support thresholds do not change that standard.
Does the change affect you?
It depends on where your case stands, not only on your schedule. Find the situation closest to yours.
Review timing now
Support hasn't been set yet
You are in a pending divorce or parentage case and the court has not entered a support order, or you expect to file soon. A support order entered after January 1 may be calculated under the new rule. Illinois's general application provision covers pending cases "with respect to issues on which a judgment has not been entered" (750 ILCS 5/801(b)), and the Act itself does not address cases pending on January 1. If temporary support is in place or the schedule is near 110 overnights, timing deserves a careful look.
The range the change reaches
Your schedule is 110 to 145 overnights
Under the old rule, a parent with fewer than 146 overnights is outside the shared-care formula. Under the new rule, 110 to 145 overnights qualifies, with the 2% to 10% adjustment. How much that changes the amount depends on both incomes and the exact count. It matters when support is set or modified under the new law.
A modification may be worth a look
You have an order, and something else has changed
A lasting change in either parent's income, the parenting schedule, or the children's needs can support a modification (750 ILCS 5/510(a)(1)). The court may apply the new rules only if it finds a substantial change in circumstances that warrants applying them. Support generally can be changed only for payments that come due after the other parent has notice of the filing, so waiting has a cost.
Not affected by itself
You have an order, and nothing else has changed
January 1 doesn't change your order, and the new law alone is not grounds to modify it, even if your schedule falls between 110 and 145 overnights. A different result from a calculator is not a new order.
The 2027 rule by the numbers
Find the overnights a year that the child spends with the parent who has less time. That number decides which formula applies.
| Overnights a year (parent with less time) | Through Dec. 31, 2026 | Beginning Jan. 1, 2027 |
|---|---|---|
| Fewer than 110 | Standard calculation | Standard calculation |
| 110–114 | Standard calculation | Shared care, plus 10% |
| 115–119 | Standard calculation | Shared care, plus 9% |
| 120–124 | Standard calculation | Shared care, plus 8% |
| 125–129 | Standard calculation | Shared care, plus 7% |
| 130–134 | Standard calculation | Shared care, plus 6% |
| 135–139 | Standard calculation | Shared care, plus 4% |
| 140–145 | Standard calculation | Shared care, plus 2% |
| 146 or more | Shared care | Shared care, no adjustment |
Standard calculation: the basic obligation from the HFS schedule is divided by the parents' income shares. The parent with less parenting time usually pays his or her share, and the receiving parent's share is presumed to be spent directly on the child (505(a)(1.5)).
Shared care: the basic obligation is multiplied by 1.5, each parent's share is multiplied by the other parent's percentage of time, and the two amounts are offset. The percentage increase applies to the shared-care obligation of the parent with fewer than 146 overnights (505(a)(3.8)).
Official worksheets: the statute directs the Illinois Department of Healthcare and Family Services to promulgate the worksheets for the shared-care calculation, including the adjustment (505(a)(3.8)(4)). An estimate is not a substitute for the official HFS materials.
Where does your schedule fall?
Enter the overnights a year the child spends with one parent. The other parent has the rest of the 365. The statute counts the overnights each parent exercises, so use a full year's calendar, including holidays and summer.
Or try a sample schedule:
Which formula applies
Parent with less time: 104 overnights. Other parent: 261.
- Through December 31, 2026
- Standard calculation (shared care needs 146 overnights each)
- Beginning January 1, 2027
- Standard calculation (shared care needs 110 overnights each)
This shows which formula applies when support is set. It does not change an existing order. Which rule applies to your case is a separate question; see Does the change affect you?
If your case is pending: file now or wait?
There is no blanket answer to whether to file now or wait until January. Two rules pull in different directions:
- Waiting has a cost. Support generally can be modified only for installments that come due after the other parent has notice of the filing (750 ILCS 5/510(a)). Waiting to file can mean more months at the current amount.
- The filing date can affect which law applies. After the Illinois Marriage and Dissolution of Marriage Act was rewritten in 2016, appellate decisions for Cook County (First District) and for Kane, Lake, McHenry, DeKalb and Kendall counties (Second District) read its application provision (750 ILCS 5/801) to reach modification petitions filed after the effective date, and pending cases only on issues without a judgment, so petitions filed before that date were decided under the old law (In re Marriage of Benink, 2018 IL App (2d) 170175, ¶¶ 27–29; In re Parentage of A.H., 2023 IL App (1st) 190572). The Fourth District read the same provision the other way (In re Marriage of Elliott, 2019 IL App (4th) 180628), and DuPage and Will counties (Third District) have no decision on the point. Public Act 104-733 has no transition rule of its own, so how courts will apply it to cases pending on January 1 is not yet settled.
The right sequence depends on your order, what has changed, and where the case stands. Parenting time is decided on the child's best interests, so a schedule should be built around the child; the support formula counts the overnights each parent exercises (505(a)(3.8)(1)). For a fuller walk-through with a worked example, read Illinois child support changes in 2027.
2027 support check
For parents whose support will be set or modified after January 1, 2027, in pending and new cases, or whose parenting schedule, income or children's needs have changed since their order. We review your order or case, run the numbers under the 110-night rule, and give you a short written answer on whether a modification or a different position makes sense. The new law by itself is not a reason to change an existing order. The fee is capped at $1,050 (two hours at $525), held in trust and applied as earned, and credited against the fees on your first statement if you then hire the firm. Call (312) 621-4394 or use the intake form and mention “2027 support check.”
Talk through your order with a lawyer
Jonathan D. Steele is a family law attorney and a partner at Beermann LLP in Chicago. He handles child support, parenting, and post-decree modification matters in Cook, DuPage, Lake, Will, and Kane counties, and he co-wrote the child support chapter of IICLE's Family Law: Child-Related Issues in Dissolution Actions (2026 Edition). See Speaking and publications.
A consultation about the 2027 change looks at:
- whether support in your case has been set, and when it will be;
- your actual overnight count, including holidays and summer;
- whether anything else has changed that could support a modification, and what changes from the date of notice; and
- how the new adjustment, and any overnight equivalents, would affect the calculation.
How to start
- Request a conflict check. Share only your name, contact information, and the names of the people involved, not the facts of your matter.
- Schedule a consultation. If the conflict check clears, the office contacts you to set a time.
- Bring what you have. Your current support order and any agreement it incorporates; the parenting plan or allocation judgment; a calendar of the overnights actually exercised over the last year; recent pay stubs, the last two tax returns, and bonus, commission, or business-income records; health-insurance and child-care costs; and any pending motion with its filing and notice dates.
Need an emergency order of protection or help with a child-safety emergency? Emergency line, 24/7: (312) 638-0897. If we can't pick up, we return emergency calls within one hour.
If anyone is in immediate danger, call 911.
Common Questions About the 2027 Change
Will my child support change automatically on January 1, 2027?
No. Public Act 104-733 changes the rules courts use when they set or modify support. It does not rewrite orders already in place, and under the amended 750 ILCS 5/510(a), the new law by itself is not a substantial change in circumstances warranting a modification. Keep following your current order until a court changes it.
Can I ask to modify my order because of the new 110-overnight rule?
Not on that basis alone. A modification requires a substantial change in circumstances (750 ILCS 5/510(a)(1)), and the court may apply the new rules in a modification only on finding a substantial change that warrants applying them. If something else has changed, such as either parent's income, the parenting schedule, or the children's needs, a modification may be worth reviewing. Support generally can be changed only for payments that come due after the other parent has notice of the filing.
My divorce or parentage case is still pending. Which rule will apply to support?
It depends on whether support has already been decided and on where the case stands. Illinois's application provision reaches pending cases on issues without a judgment (750 ILCS 5/801(b)), but Public Act 104-733 does not address cases pending on January 1. Review the timing of any temporary or final support order with counsel.
Does the change apply to parents who were never married?
Yes. In parentage cases, the court sets child support using the guidelines in Section 505 of the Illinois Marriage and Dissolution of Marriage Act (750 ILCS 46/802(a)).
How many overnights does a typical schedule have?
Alternating weekends plus one weeknight every week is about 104 overnights a year, below the new threshold. If each alternating weekend runs through Sunday night, the same schedule is about 130. Holidays and summer change the count. Parenting time is still allocated according to the child's best interests (750 ILCS 5/602.7(a)), not to reach a support threshold.
What if each of us already has 146 or more overnights?
The shared-care formula already applies. The new percentage adjustment applies only to a parent with 110 to 145 overnights (750 ILCS 5/505(a)(3.8)(3)).
Does the calculator on this site use the 2027 rule?
Beginning January 1, 2027, it applies the new rule automatically, and before then you can preview the 2027 rule. It uses the HFS schedule and gross-to-net table effective March 20, 2026, with standardized net income. Its result is still an estimate: it does not take individualized net income, maintenance, or support paid for other children, and the official HFS worksheets control.
Related guides and tools
Official sources
- Public Act 104-0733 (SB 3524)
- 750 ILCS 5/505, child support
- 750 ILCS 5/510, modification
- 750 ILCS 5/801, application to pending cases
- Illinois HFS income shares schedule and worksheets
Statutory text on this page was checked against the official text on ilga.gov in October 2026.
Attorney advertising. This page provides general information about Illinois law. It is not legal advice for your situation, and reading it does not create an attorney-client relationship. Legal services are provided through Beermann LLP, 161 N. Clark St., Suite 3000, Chicago, IL 60601. Jonathan D. Steele is licensed to practice law in Illinois. Sample schedules and overnight counts are illustrations, not predictions of any result. Statutes and rules change; the linked official sources control.